I'm not a ZTR owner or expert by any means, but some thoughts as I looked into this company:
They have been around since 1998, and have a bit of a global market, so they probably are not going anywhere unless MTD buys them out LOL!
A filter would not be a problem as they look to use the same engine and hydro drive lines everyone else does.
If you have a local dealer who is supporting and servicing the machines, a dealer network would not be necessary unless you move or that dealer went out of business. Parts look to be available direct from the manufacturer.
As for the model you are considering, have you researched the Briggs Intek engine? I'll do it for you: It is the most inexpensive small engine money can buy that is installed on an OEM machine. I'd say no to that feature right away. Dollar for dollar, a Cub Cadet Tank with Kawasaki engine would be a better buy IMHO. But like I said, I'm not a ZTR guy. For those who stated that there are better buys who own these things, tossing a few names around as to what you recommend might be of help.
-Fordlords-